Glucopyranosiduronates reactions

The metabolite of 2-amino-4-phenylthiazole (used as an anaesthetic for fish) was identified (223) as 2-amino-4-phenylthiazole 2-N, -d-glucopyranosiduronic acid (71) (Scheme 50). The formation of this compound probably involves the reaction of the exocyclic nitrogen on the Open-chain form of the acid. The isolation of this metabolite is part of a very Systematic study by Japanese researchers related to the anaesthetic... 

Early attempts to prepare phenyl a- and /3-D-glucopyranosiduronic acid by this reaction were not always successful.However, by performing the oxidation at a slightly higher temperature (about 90°) and at pH 8-10, and by using more catalyst, it has been found possible to obtain both compounds - the use of really fresh catalyst is also important. The following modification of the original procedure for the preparation of the or anomer has been found to improve the yield nearly four-fold. 

No. D Glucopyranosiduronic add Oxidizing agent Catalyst Reaction time, hr. Temperature, °C. Yield, % Conditions, comments Refer- ences ... 

Condensation of the appropriate per-O-acetylated glycopyranosyl bromide with 4-aminobenzenethiol in the presence of sodium methoxide has been used to prepare 4-aminophenyl l-thio-j3-D-gluco-, -galacto-, and -xylo-pyranosides and 4-aminophenyl 2-acetamido-2-deoxy-1 -thio-jS-D-glucopyranoside. 4-Amino-phenyl l-thio-/3-D-glucopyranosiduronic acid was synthesized by condensation of methyl (2,3,4-tri-O-acetyI-a-D-glucopyranosyl bromide)uronate with 4-aminobenzenethiol, followed by saponification with sodium hydroxide. An attempt to obtain the l,2-ci5-l-thioaldopyranoside by reaction of 4,6-di-0-acetyl-2,3-0-carbonyl-a-D-mannopyranosyl bromide (191) with sodium 4-nitrobenzene-... 

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